1. Field of the Invention
The invention is directed to tooling for metalworking operations and, more particularly, directed to cutting inserts and the toolholder for holding such inserts during metalworking operations, such as turning.
2. Description of Related Art
In turning operations, one of the primary criteria for selecting an appropriate insert is the required nose angle. The nose angle is defined at the cutting point in a cutting portion of the insert made up of two straight lines meeting at that point. There are turning inserts referred to as 80° diamonds, 55° diamonds and 35° diamonds, whereby these numerical values define the angle the two sides form with the cutting point. Typically, these inserts are symmetric with two opposing cutting regions. These inserts may also be indexable.
In the past, each cutting insert having a different nose angle would require a dedicated toolholder having a pocket conforming to the shape of the unengaged cutting portion of that insert, thereby requiring a toolholder for every different insert shape.
U.S. Pat. No. 6,152,658 is directed to a modular cutting tool assembly whereby, as illustrated in FIG. 2, a plurality of different inserts may be accepted by the pocket of a single toolholder. However, the pocket of this toolholder is suitable to accept a variety of different inserts only because the pocket has been formed to accommodate each of the different shapes of these inserts. As a result, any one insert may not be supported optimally because portions of the toolholder pocket have been recessed and carved out to accommodate cutting inserts of other shapes.
Therefore, one object of the present invention is to provide a cutting insert having a standardized core with a desired cutting portion such that a variety of other cutting inserts having the same standardized core, but different cutting portions, may be utilized in a common toolholder, thereby minimizing the need to maintain in inventory a large number of different toolholders.
A further object is to provide a single toolholder that will accept these differently shaped inserts.
Additionally, during some metalworking operations, space is limited and the tip-to-tip length of a particular standard cutting insert used for tuning operations may be excessive. In particular, for small cutting tools, such as those cutting inserts having an IC (inscribed circle) of ¼ inch or less, space is limited and it is desired, if possible, to reduce the tip-to-tip length between cutting inserts while, at the same time, maintaining the strength and integrity of those inserts.